1. Field of the Invention
The present invention relates to a terminal extracting structure for a solar cell module and, more particularly, to a terminal box which is to be attached to a solar cell module and which has improved attaching workability and adhesion reliability.
2. Related Background Art
A solar cell module is conventionally known in which a solar cell element is sealed with a resin on a reinforcing plate, e.g., a steel sheet or a glass sheet, and is further covered with a protective film. As the protective film, a weather-resistant film such as a glass or fluoroplastic film is used.
As the solar cell element, a crystalline silicon solar cell, a polysilicon solar cell, an amorphous silicon solar cell, a copper indium selenide solar cell, a compound semiconductor solar cell, and the like are available. Of these solar cells, thin-film crystalline silicon solar cell, compound semiconductor solar cell, and amorphous silicon solar cell are recently studied and developed extensively in various fields as they can be formed to have a large area at a comparatively low cost.
As the lower surface reinforcing material of the solar cell module, a weather-resistant, moisture-resistant film obtained by sandwiching an aluminum foil with weather-resistant films, a thin steel sheet, e.g., non-coated zinc-plated steel sheet, a steel sheet which is coated with a polyester resin or acrylic resin so as to have high flexibility and hardness, a plastic sheet, or the like is used.
The output terminal of the solar cell module is connected with a screw, a lead wire, or a socket. In any case, a terminal box having a water-proof structure is often provided for the purpose of insulation. Such a terminal box is adhered to the lower surface of the solar cell module with a double-sided adhesive tape or is mounted on it with an adhesive, e.g., silicone sealant. In the former case, the mounting operation is very simple, and a desired original adhesion strength can be easily obtained by determining the pressure to be applied.
Japanese Laid-Open Patent Application No. 7-273361 describes a solar cell module obtained by sealing a solar cell element on a steel sheet with a resin, adhering a terminal box for obtaining power from the prospective solar cell module covered with a protective film, to the solar cell element with a double-sided adhesive tape, and successively filling the terminal box with a filler through a through hole formed in the terminal box.
When the terminal box is adhered only with the double-sided adhesive tape, a sufficiently large holding force cannot be obtained under a high humidity and a high temperature. The adhesion strength of the terminal box onto the solar cell module may be decreased due to expansion of the internal air or the like. When the terminal box is adhered with an adhesive, after the terminal box is mounted, the adhesive must be sufficiently solidified so that the terminal box will not separate in the solar cell module inspecting process, leading to a poor productivity.
When the terminal box is fixed by adhesion while employing the double-sided adhesive tape as well for the purpose of preliminary fixing, in particular, when a compact terminal box having a small adhesion surface is mounted, the adhesive may undesirably enter the gap between the double-sided adhesive tape and the solar cell module. Then, an adhesion strength necessary for sending the solar cell module to the inspection/wrapping process cannot be obtained, and the terminal box may be dislocated on the adhesion surface of the solar cell module or the adhesion strength may be decreased. When the adhesive enters the gap in this manner, the adhesive does not sufficiently spread over the adhesion surface, and an adhesion strength necessary in terms of design cannot be obtained.